Prior art modems suffer from the disadvantage of requiring steady uninterrupted dial tone in order to dial out. The presence of at least one unheard message in a voice mailbox for a subscriber's line, in connection with which a central office Call Answer feature has been activated, causes an interrupted or stuttered dial tone on the line. In order for the modem to dial out, the interrupted or stuttered dial tone must be returned to its regular uninterrupted state, which requires the subscriber of the phone line to retrieve unheard messages from the voice mailbox. The inability of prior art modems to dial out in the presence of interrupted dial tone imposes delays in modem activation and frustration for the modem user who wishes to have quick access to on-line features via the modem.